The present invention relates generally to image processing systems and, more particularly, to methods and systems for automatically cropping an image.
Cropping an image refers to cutting away and discarding portions of the image. Cropping techniques evolved due to, among other things, challenges associated with precisely capturing a desired image using an image capture device, e.g., a camera. Photographic composition requires time and attention, which may not be available to a photographer in the act of capturing images of e.g., action events. Thus, after the fact, it may be desirable to change the focal point of the image by cropping the image. Today many images can be captured electronically and subsequently processed using image processing software. For example, many photo editing applications include a crop tool. Using the crop tool typically involves selecting the area to retain, refining the selection, and finalizing the crop action. Once the cropping procedure is finalized, the area outside the crop selection can be discarded.
Another area in which cropping can be used is in thumbnail generation. Thumbnails are small versions of original images which can be used, for example, in image retrieval or browsing systems. However, sometimes when an image is shrunk to create a corresponding thumbnail, it is no longer easily recognizable as representative of the original image. Accordingly, cropping can be used to reduce the size of an original image, prior to shrinking, in a way which captures important features of the original image and discards less important pixels.
Although cropping is typically performed manually, the growing reuse of objects and images in automated processes suggests that automated cropping is desirable. For example, automatic image cropping is one significant component of advanced Variable Data Printing (VDP) systems, which can personalize both the text and image contents based, e.g., on a user's preferences and demographic profile. For some applications, the copy hole 100 for the original image is rectangular so that the automatic image cropping function only needs to determine a rectangular-shaped cropping area as shown in FIG. 1(a). However, for other applications, e.g., professional publishing applications, the copy hole 120 can be non-rectangular, e.g., as shown in FIG. 1(b). Accordingly, it would be desirable to provide methods, devices and systems for automatically cropping images into resulting shapes that are non-rectangular.